Many diseases are due to the immunoprotection of the body having become unbalanced by the formation of undesirable fractions in the blood. For example, in cases of haemophilia, antibodies may be formed against factor VIII or factor IX which normally control the coagulation of the blood.
It is an object of the present invention to remove such undesirable fractions. It is another object to separate the removed fraction for further usage. For example, the antibodies against factor VIII or factor IX in turn may be attached to a column for the separation of just factor VIII or just factor IX from other fluids, such as blood or plasma from blood donors.
If it is desired to remove just the said antibodies against factor VIII or factor IX, a column is used in accordance with the invention comprising just factor VIII or factor IX attached to a carrier. Alternatively, for example, protein A can be bound to the carrier which in turn is capable of binding, among other things, several different types of IgG. It will thus be evident to those of ordinary skill in this art that the invention can be used in conjunction with a number of different adsorption substances.
A known technique for the removal of a fraction in a biological fluid is described in the journal Blood, vol. 58, No. 1, July, 1981 by Inga Marie Nilsson, Svante Jonsson, Siv-Britt Sundqvist, Ake Ahlberg and Sven-Erik Bergentz under the title "A Procedure for Removing High-Titre Antibodies by Extracorporeal Protein-A-Sepharose Adsorption in Haemophilia: Substitution Therapy and Surgery in Patients with Haemophilia B and Antibodies." It can be also be applied, however, as mentioned previously, in a more general manner.
In accordance with the aforementioned paper, it is known that, for example, plasma can be separated from whole blood and that, subsequently, factor VIII or factor IX antibodies can be separated from this plasma in one or the other of two columns connected in parallel containing protein A attached to agarose of the type which is sold under the name of Sepharose by Pharmacia Chemicals, Uppsala. When one column has become saturated, the plasma in turn is passed over to the parallel column so as to make possible a regeneration of the first-mentioned column. Prior to this regeneration, the remaining plasma in the column is pressed back to the patient with the help of a flushing liquid. Towards the end of the flushing, the patient is disconnected, and the flushing liquid is passed to a drain. Subsequently, the pH of the column is lowered gradually by means of a further flushing through, this time with the help of a mixture of an acid and a base. When the attached fractions have become detached from the column, this is indicated on a succeeding UV-meter, which in combination with a succeeding pH-meter, conveys the flushing liquid, together with separated fractions, either to a drain or to a collecting receiver just for these fractions.
One disadvantage of this known system, however, is that it requires a UV-meter of such sensitivity that it is unsuitable for disposable usage and can only be reused after sterilization. A further disadvantage thereof is the gradual lowering of the pH of the column, which takes a relatively long time compared to the time required for the detachment of the collected fractions.